1. Field of the Invention
The present invention relates to a sorter-finisher, which is attachable so that sheets ejected from a copying machine or the like are distributed and stored into a plurality of bins, whereby one set of the sheets are then taken out of each bin to be stapled by a stapler.
2. Description of Related Art
Recently, responding to the increasing demand for automated paper handling system for the copying machines, the optional systems such as the automatic document feeding system and the sorting system designed for sorting or grouping copied sheets have been developed and commercialized in various types one after another. The users of the copying machines are now requiring the sorter-finisher capable of automatically stapling and stacking sheets which have been distributed in the sorting system, and this type sorter-finisher has already been commercialized for some of large-sized copying machines.
With a conventional sorter, each bin is elevated so as to form an angle in the sheet storing direction. Therefore, in order to prevent sheets stored in each bin from sliding down, a claw for preventing sheets from sliding down is protruded at the rear end of each bin relative to the sheet storing direction. In the case of the claw for preventing sheets from sliding down that is protruded as above, when the sorting function is independently used, there is no problem because sheets have only to be dropped one by one into each bin. However, when the stapling function is used in addition to the sorting function, there is a problem in that one set of sheets, when taken out of each bin, has to go over the claw for preventing sheets from sliding down, resulting in a structurally complex apparatus. For example, the above problem can be solved by providing an arrangement, wherein a guide plate is provided in order to move up from below a bin so as to elevate the end portion of sheets. However, this arrangement requires that a large notch should be formed at the end portion of the bin, thus causing a problem in strength. Further, such a guide plate is allowed to cover only a part of one set of sheets, but not the whole area of one set of sheets relative to the widthwise direction thereof. Therefore, one set of sheets curled downward is difficult to go over the claw with certainty for preventing sheets from sliding down.